Method of treatment of calcium disorders using aminoalkane-diphosphonic acids

ABSTRACT

A method for the treatment of diseases relating to the abnormal deposition or dissolution of difficultly soluble calcium salts in the body or mouths of warm-blooded animals which consists of administering orally, parenterally or topically to said warm-blooded animals, a safe but effective amount of at least one pharmacologically acceptable aminoalkane diphosphonic acid derivative or a water-soluble salt thereof.

This is a division of Ser. No. 529,039, filed Dec. 3, 1974, now U.S.Pat. No. 3,962,432.

A number of diseases are known in human and veterinary medicine whichare associated primarily or partly with the abnormal deposition ordissolution of difficulty soluble calcium salts in the animal body.These diseases can be divided into two categories:

(1) Abnormal depositions of difficulty soluble calcium salts, mostlycalcium phosphate which, cause bone malformations, pathologicalhardening of tissues and secretions in organs;

(2) The abnormal dissolution of hard tissues, which causes losses ofhard bone substance which cannot be replaced or which are replaced onlyby incompletely crystallized tissue. This dissolution is frequentlyaccompanied by pathologically high calcium and phosphate concentrationsin the plasma.

In the first category belong diseases like arthritis, neuritis,bursitis, tendonitis and other inflammatory diseases where the depositof calcium phosphate is enhanced in the respective body parts.Hyperparathyroidism caused by hormonal disorders can, in combinationwith hypercalcemia, produce a calcium deposit in many organs. Myositisossificans (fibrodysplasia) leads to progressive ossification of themusculature, and in Bechterew's disease, a typical inflammatory disorderof the bone joint system, progressive calcification leads to anossification of the entire vertebral system.

Particularly frequent among the diseases of the first category isarteriosclerosis, where calcification of the aorta and of the arteriesappears as a rule in the progressive stage. Furthermore, calculi of allkinds belong here, like kidney stones, gall stones, bladder stones andsialolith (tartar). Even though these stones do not consist completelyof calcium phosphate, a calcium phosphate deposit can be assumed in mostcases as a nucleus.

To the second category of diseases belong hereditary hypophosphatasia aswell as osteoporosis, where there is insufficient reformation of bonesubstance for various reasons (senile, menopausal, caused by treatmentwith drugs like steroids, or by diseases, like arthritis). Furthermore,this group comprises Paget's disease (Osteitis deformans) where thedissolution of normal bone substance is accompanied by reformation ofsoft, only slightly crystallized tissue, as well as Osteodystrophiafibrosa generalisata, a systemic disease with irregular bonedisintegration.

A number of these diseases appear relatively frequently in human, aswell as in veterinary medicine. A completely satisfactory therapy forthese diseases has not yet been described, though controlled diets,treatment with fluorides, phosphates or condensed phosphates, with sexhormones, and particularly with the hormone calcitonin have beensuggested and also used. In the last years the treatment of some ofthese diseases with phosphonates has been suggested. In addition U.S.Pat. No. 3,584,124 suggests treating some of these diseases withethane-1,2-dihydroxy-1,2-dicarboxy-1,2-diphosphonic acid and its salts.

It has also been suggested to add chemical substances to oral hygieneproducts and dentrifices in order to prevent the deposition and causethe dissolution of the difficulty soluble calcium salts known as tartar.Such deposits are frequently removed by mechanical means. As chemicallyactive agents, compounds like ethylene diamine tetraacetic acid ornitrilo-triacetic acid have been added to toothpaste, mouthwashes orspecial ointments. While these toothpastes and mouthwashes serveprimarily for the prophylactic treatment of tartar formation, specialointments, which are applied to the teeth and remain there for sometime, have the function of removing the tartar or at least making iteasier to remove. But these products have not been greatly used inpractice so far, because they must meet a number of differentrequirements. First, such cosmetic preparations must bepharmacologically harmless, particularly since they can be accidentallyswallowed. The agents should prevent the formation of tartar withoutdestroying the tooth structure. Besides, they must not cause anyirritation of the gums or of the mucous membrance of the mouth.

An object of the present invention is the development of therapeuticmethods and pharmacological preparations which may be utilized in thetreatment of the above conditions.

Another object of the present invention is the development of a methodfor the treatment of diseases relating to the abnormal deposition ordissolution of difficultly soluble calcium salts in the body or mouthsof warm-blooded animals which consists of administering orally,parenterally or topically to said warm-blooded animals, a safe buteffective amount of at least one pharmacologically acceptableaminoalkane-diphosphonic acid derivative or a water-soluble saltthereof.

A further object of the present invention is the development of apharmaceutical composition consisting essentially of a minor amount ofat least one pharmacologically acceptable aminoalkane-diphosphonic acidderivative or a water-soluble salt thereof, and a major amount ofpharmacologically acceptable excipients.

These and other objects of the present invention will become moreapparent as the description thereof proceeds.

The invention concerns pharmaceutical or cosmetic preparations toinfluence the deposition and dissolution of difficultly soluble calciumsalts by using certain aminoalkane diphosphonic acids or their nontoxicpharmacologically acceptable water-soluble salts as an activeingredient, as well as the method of using the acids or their salts toinfluence this deposition or dissolution of these difficultly solublecalcium salts.

It was found that aminoalkane-diphosphonic acids or their water-solublesalts are suitable for the therapeutic treatment of disorders of calciumor phosphate metabolism and of diseases caused by them. The newpharmaceutical or cosmetic products for influencing the deposition anddissolution of difficultly soluble calcium salts are, therefore,characterized by the fact that they contain as an active ingredient anontoxic effective amount of an aminoalkanediphosphonic acid of theformula ##STR1## or the nontoxic pharmacologically acceptablewater-soluble salts, where R₁ and R₂ are hydrogen or alkyl having 1 to 3carbon atoms. Specifically all the compounds indicated in Table I beloware suitable, but 3-amino-1-hydroxypropane-1,1-diphosphonic acid ispreferred.

More particularly, therefore, the present invention relates to a methodfor the treatment of diseases relating to the abnormal deposition ordissolution of difficultly soluble calcium salts in the body or mouthsof warm-blooded animals which consists of administering orally,parenterally or topically to said warm-blooded animals, a safe buteffective amount for said treatment of at least one pharmacologicallyacceptable aminoalkane-diphosphonic acid derivative selected from thegroup consisting of

(A) at least one aminoalkane-diphosphonic acid of the formula ##STR2##wherein R₁ and R₂ are each selected from the group consisting ofhydrogen and alkyl having 1 to 3 carbon atoms, and

(B) a nontoxic pharmacologically acceptable water-soluble salt of (A);as well as a pharmaceutical composition consisting essentially of aminor amount of at least one pharmacologically acceptable aminoalkanediphosphonic acid derivative mentioned above and a major amount ofpharmacologically acceptable excipients.

The aminoalkane-diphosphonic acids of the above mentioned type can beobtained by reacting β-alanine or β-alanine alkylated on the nitrogenatom with phosphorus trichloride and phosphorous acid. The reaction cantake place in the presence or absence of an organic diluent.

Specific examples of these aminoalkane-diphosphonic acids are

3-amino-1-hydroxypropane-1,1-diphosphonic acid,

3-(dimethylamino)-1-hydroxypropane-1,1-diphosphonic acid,

3-(diethylamino)-1-hydroxypropane-1,1-diphosphonic acid,

3-(dipropylamino)-1-hydroxypropane-1,1-diphosphonic acid,

3-(ethylpropylamino)-1-hydroxypropane-1,1-diphosphonic acid,

3-(methylamino)-1-hydroxypropane-1,1-diphosphonic acid,

3-(ethylamino)-1-hydroxypropane-1,1-diphosphonic acid, and

3-(propylamino)-1-hydroxypropane-1,1-diphosphonic acid.

Table I below sets forth the formulae for the above-mentioned compounds.

                  TABLE I                                                         ______________________________________                                         ##STR3##                                                                      ##STR4##                                                                      ##STR5##                                                                     wherein n is an integer from 1 to 2                                            ##STR6##                                                                      ##STR7##                                                                      ##STR8##                                                                     ______________________________________                                    

instead of the free acid, its pharmacologically acceptable,water-soluble salts, for example, the alkali metal salts such as thesodium or potassium salts, the magnesium salts, the ammonium salts andsubstituted ammonium salts, such as lower alkylammonium and loweralkanolammonium salts, such as mono-, di- or tri-ethanol-ammonium saltscan also be used. For pharmaceutical applications, both the partialsalts, in which only a part of the acid proton is substituted by othercations and full salts can be used, but partial salts which reactsubstantially neutral in aqueous solution (pH 5 to 9) are preferred.Mixtures of the above salts can also be employed.

The dosage range of the aminoalkane-diphosphonic acid derivatives isvariable and depends on the respective conditions, such as the type andseverity of the disease, duration of the treatment, and the particularcompound being utilized. Individual dosages can be from 0.05 to 500 mgper kg of the warm-blooded animal body weight. The preferred dose is 1to 50 mg per kg of body weight, and can be administered up to four timesdaily. The higher doses are necessary for oral application, due to thelimited resorption. In longer treatments, after initial higher doses,lower doses are normally required to maintain the desired effect.

Doses under 0.05 mg per kg of body weight have little effect on thepathological calcification or dissolution of hard tissue. Doses above500 mg/kg of body weight may have toxic side effects in the long run.The aminoalkane-diphosphonic acid derivatives or their salts can beadministered orally, and, in hypertonic solution, subcutaneously,intramuscularly and intravenously in the form of tablets, pills,capsules or as injectable solutions. For certain animals theseaminoalkane-diphosphonic acid derivatives can also be used as part ofthe feed or of feed additives.

The preferred dosage for these various methods of administration are, inmg/kg:

    ______________________________________                                        Orally                1 to 50                                                 Subcutaneously        1 to 10                                                 Intramuscularly       0.05 to 10                                              Intravenously         0.05 to 2                                               ______________________________________                                    

The aminoalkane-diphosphonic acid to be used according to the inventionis generally added in the form of its alkali metal salts to thecorresponding oral hygiene products and dentrifices, such astoothpastes, mouthwashes, tooth cleaning powders, mouth lozenges,chewing gum, and tooth treatment ointments in amounts of 0.01% to about5% by weight. Oral hygiene products which are necessarily swallowed,like mouth lozenges and chewing gum, should only contain small amountsof up to about 1% by weight; those that are frequently swallowed byaccident should not contain more than about 2.5% by weight. The highestamounts can be incorporated in tooth treatment ointments which are usedlocally by the dentist for the treatment of acute cases.

The pH value of the oral hygiene products and dentrifices according tothe invention can range from 5 to 9. The lower limit should not be setlower for safety reasons, to prevent damage to the tooth enamel in acombination of unfortunate circumstances, despite the great safety inthe treatment with aminoalkane-diphosphonic acid. The upper limitresults from practical considerations, since it is not possible toproduct alkaline products which are satisfactory in aroma and taste.

The suitability of the aminoalkane-diphosphonic acid derivatives to beused according to the invention for the therapeutic and prophylactictreatment of tartar results from its capacity of inhibiting even insmall amounts crystallization in the precipitation of calcium apatite.Calcium-apatite, which is precipitated in the presence ofaminoalkane-diphosphonic acid, is X-ray amorphous, in contrast tocrystalline apatite which is usually formed without this addition.

In mouthwashes, a combination with the aqueous-alcoholic solution ofvarious types of essential oils, emulsifiers, wetting agents,antiseptics, astringents and tonicizing drug extracts, caries-preventingadditives, and flavor correctives can be readily used. Hydrogenperoxide-containing mouthwashes, which can be used to preventparadontosis, can also be provided with the additive according to theinvention.

The toothpastes are generally pasty preparations of water, thickeners,wetting and foaming agents, moisturizers, abrasives, scouring andcleaning agents, aromas, flavor corrective, antiseptics and othervaluable oral-cosmetic substances. The cleaning agents and otheradditives to be used in the toothpastes according to the inventionshould, as far as possible, be free of soluble calcium in order not toimpair the tartar-preventing action of the aminoalkane-diphosphonicacids.

The cleaning agents are, therefore, primarily secondary calciumphosphate, sodium metaphosphate, precipitated silicas, aluminumsilicates, calcium pyrophosphate, and finely dispersed synthetic resins,like melamine-urea-formaldehyde resins or polylower alkylmethacrylates.The content of cleaning agent in the toothpastes is generally between 25and 60%. The wetting and foaming agents used are primarily soap-freeanionic surface-active compounds, like fatty alcohol sulfates, e.g.,sodium lauryl sulfate, monoglyceride sulfides, sodium laurylsulfoacetate, sarcosides, taurides and other anionic surface-activecompounds which do not influence the taste in amounts of 0.5% to 5%. Forthe production of the binder for the toothpastes, all thickeners thatare customary for this purpose can be used, like hydroxyethyl cellulose,sodium carboxymethyl cellulose, tragacanth, carragheen, agar, gumarabic, as well as additional finely dispersed silicas. The moisturizersare primarily glycerin and sorbitol in amounts of up to about one-thirdof the total agent. The desired aroma and flavor can be achieved by theaddition of essential oils, like peppermint, clover, wintergreen orsassafras oil, as well as sweetening agents, like saccharin, dulcin,dextrose, levulose, etc. In addition, caries-preventing additives, likefluorides or fluorphosphates can be used. The content of thetartar-preventing aminoalkane-diphosphonic acid to be used in thetoothpastes according to the invention is between 0.01 and 5%,particularly 1% and 4%, related to the total mass of the toothpaste.

The activity of the compounds listed in Table I and particularly of3-amino-1-hydroxypropane-1,1-diphosphonic acid or a nontoxicpharmacologically acceptable water-soluble salt of the above mentionedcompounds is probably due to an interaction of the phosphonic acid withthe crystal surface of the calcium phosphate.

The effects that can be achieved with the new pharmaceuticalpreparations can be demonstrated by the tests and applications describedin the following examples. These examples are illustrative of thepractice of the invention without being limitative thereof in anyrespect.

EXAMPLE 1 Apatite Crystallization Delay Test in Vitro

The compounds utilized according to the invention are efficient inpreventing abnormal calcium depositions. Their efficacy in this respectwas demonstrated in vitro by their retarding the crystallization ofapatite.

Supersaturated solutions of Ca++ and HPO₄ -- ions are relatively stable,but crystallize after the addition of apatite nuclei according to thereaction

    5 Ca++ + 3 HPO.sub.4 -- + H.sub.2 O → Ca.sub.5 (PO.sub.4).sub.3 OH + 4 H.sup.+

with the release of protons. The reaction can, therefore, be readilyobserved by titration with a base at a constant pH.

400 ml of 0.0008 molar KH₂ PO4 solution were mixed with 45 ml of a 0.012molar CaCl₂ solution, and the clear solution was standardized with KOHto a pH of 7.4, after being brought to a temperature of 35° C. After 30minutes during which time the pH did not change, a suspension of 100 mgof hydroxyl apatite in 50 ml of H₂ O was added. The crystallization setin immediately and was followed by "pH-Stat" titration with 0.05 N KOH.

If a small amount of one of the aminoalkane-diphosphonic acids of theinvention, and particularly 3-amino-1-hydroxypropane-1,1-diphosphonicacid was added to the solution before the apatite was added, thecrystallization was greatly delayed. The inhibition of thecrystallization was 75% after 8 hours at a concentration of 4 mg/l, and90% after 8 hours at a concentration of 20 mg/l. Even after 14 hours thevalues are still considerably lower than those of the test without theaddition of inhibitors.

EXAMPLE 2 Retardation of the Dissolution of Calcium Hydroxyl Apatite

The dissolution of calcium hydroxyl apatite crystals in a solutionbuffered to pH 7.0 is delayed by small amounts of3-amino-1-hydroxypropane-1,1-diphosphonic acid. This can be shown by thefollowing test.

50 ml of a 0.1 molar sodium barbital solution (prepared by dissolving18.42 gm of 5,5-diethyl-barbituric acid with 0.1 mol of NaOH in 1 literof water) were mixed a weighed amount of3-amino-1-hydroxypropane-1,1-diphosphonic acid. The solution was dilutedto 450 ml and brought to a pH of 7.0 with 0.1 N HCl. Subsequently, 5.78gm of KCl were added and the solution is brought to exactly 500 ml.

1 gm of hydroxyl apatite was added to the buffer solution thus prepared,and the suspension was stirred in a closed bottle for 15 hours at 25° C.After filtration through a Millipore filter (pore with 1 to 2 μm), theclear solution was concentrated to 100 ml, and calcium oxalate wasprecipitated with the addition of 20 ml of a saturated sodium oxalatesolution. The precipitate was centrifuged off. The residue was broughtinto solution with 10 ml of fuming nitric acid and the calcium in theaqueous solution was titrated by complexometry.

The following values were reported below in Table II.

                  TABLE II                                                        ______________________________________                                        3-Amino-hydroxypropane-                                                                        Calcium   % Reduction of the                                 1,1-diphosphonic acid (mg)                                                                     (mg/l)    dissolution                                        ______________________________________                                        0                16.0      --                                                 5                15.4      3.8                                                10               10.5      33.8                                               20               9.8       38.8                                               ______________________________________                                    

With a concentration of 40 mg of the3-amino-1-hydroxypropane-1,1-diphosphonic acid in 1 liter of the apatitesuspension, a 40% reduction of the dissolution was obtained.

EXAMPLE 3 Prevention of Hardening of the Aorta in Rats

The effectiveness of the aminoalkane-diphosphonic acids particularly3-amino-1-hydroxypropane-1,1-diphosphonic acid in preventing abnormalcalcium deposits in vivo in rats can be demonstrated as follows.

This test was based on the observation that high doses of Vitamin D₃cause a considerable hardening of the aorta in rats. 30 Female ratsweighing 150 to 200 gm each were divided into three groups of 10 animalseach. They received during the test period of normal diet and tap waterand libitum. One group of 10 animals (control) received no furthertreatment. Another group of the animals received from 3rd to the 7thday, 75,000 units of vitamin D₃ daily through a stomach sound. The thirdgroup likewise received from the 3rd to the 7th day, 75,000 units ofvitamin D₃ daily through a stomach sound and, in addition, likewiseorally, 10 mg per kg of 3-amino-1-hydroxypropane-1,1-diphosphonic acidfrom the 1st to the 10th day. After 10 days the animals were sacrificedand their aortas prepared and dried for 12 hours at 105° C. Afterdetermination of the dry weight, the aortas were ashed; the residue wasdissolved, and the calcium was determined by flame photometry. Thetreatment with 3-amino-1-hydroxypropane-1,1-diphosphonic acid reducedthe vitamin D₃ induced hardening of the aortas of rats considerably.

In Examples 1 to 3, comparable results were obtained when any one of theother 3-amino-1-hydroxypropane-1,1-diphosphonic acids listed in Table I,or a nontoxic pharmacologically acceptable water-soluble salt, eitherthe partial salt or the complete salt, were substituted for the specificcompound utilized in these examples. Specific examples of these saltsinclude the sodium salt, potassium salt, magnesium salt, ammonium salt,or the mono-, di- or triethanol ammonium salt.

The following examples 4 and 5 illustrate a few dosage unit compositionscomprising a compound used according to the present invention as anactive ingredient.

EXAMPLE 4

Capsules

The capsule filler composition was compounded by known methods from thefollowing ingredients:

    ______________________________________                                        3-Amino-1-hydroxypropane-1,1-diphosphonic acid                                                             100 mg                                           Starch                       20 mg                                            Sodium lauryl sulfate        1 mg                                             ______________________________________                                    

The capsule contained an effective dosage unit composition for thetreatment of diseases relating to the abnormal deposition or dissolutionof difficultly soluble calcium salts in a warm-blooded animal.

EXAMPLE 5

Tablets

The tablet composition was compounded by known methods from thefollowing ingredients:

    ______________________________________                                        Disodium salt of 3-amino-1-hydroxypropane-1,1-                                diphosphonic acid          100 mg                                             Lactose                    100 mg                                             Starch                     47 mg                                              Magnesium stearate         3 mg                                               ______________________________________                                    

Each tablet contained an effective dosage unit composition for thetreatment of diseases relating to the abnormal deposition or dissolutionof difficultly soluble calcium salts in a warm-blooded animal.

Analogous results are obtained when any one of the other compoundslisted in Table I or a non-toxic pharmacologically acceptablewater-soluble, partial or complete, salt thereof is substituted for theparticular compound in Examples 4 and 5. Likewise, the amount of activeingredient in these illustrative examples may be varied to achieve thedesired dosage unit range and the amounts and nature of the inertpharmaceutical carrier ingredients may be varied to meet particularrequirements.

EXAMPLE 6 Oral Preparations

When 3-amino-1-hydroxypropane-1,1-diphosphonic acid or a nontoxicpharmaceutically acceptable water-soluble salt were used in mouth washesand tooth pastes, the formation of tartar is greatly reduced. The pHvalue of the mouthwashes or tooth pastes according to the invention canvary between 5 and 9.

The following recipes are suitable as a basic formula for tooth pastes:

    ______________________________________                                                             Parts by Weight                                          ______________________________________                                        (a)   Glycerin             60.0                                                     Water                13.5                                                     Sodium carboxymethyl-cellulose                                                                     0.6                                                      Silicic acid xero gel                                                                              20.0                                                     Sodium laurylsulfate 2.0                                                      Essential oils       1.0                                                      Sweetening agent     0.4                                                      3-Amino-1-hydroxypropane-1,1-                                                 diphosphonic acid    2.5                                                (b)   Glycerin             30.0                                                     Water                18.5                                                     Sodium carboxymethyl-cellulose                                                                     1.0                                                      Aluminum hydroxide   44.0                                                     Sodium laurylsulfate 1.0                                                      Pyrogenic silica     1.5                                                      Essential oils       1.5                                                      Sweetening agent     0.5                                                      3-Amino-1-hydroxypropane-1,1-                                                 diphosphonic acid    2.0                                                ______________________________________                                    

Suitable as a basic formulation for mouthwashes is the following recipe:

    ______________________________________                                                            Parts by Weight                                           ______________________________________                                        Ethyl alcohol         19.5                                                    Glycerin              7.5                                                     Water                 70.0                                                    Essential oils        0.2                                                     Sodium laurylsulfate  0.1                                                     Antiseptic (chlorothymol)                                                                           0.1                                                     Sweetening agent      0.1                                                     3-Amino-1-hydroxypropane-1,1-                                                 diphosphonic acid     2.5                                                     ______________________________________                                    

Any one of the compounds described in Table I or a nontoxicpharmacologically acceptable water-soluble, partial or complete, saltmay be substituted for the specific compound utilized; and comparableresults are achieved.

By regular use of the toothpastes and/or mouthwashes containing3-amino-1-hydroxypropane-1,1-diphosphonic acid, or its salts such as thesodium salt, the formation of tartar could be considerably reduced.

The formation of hard compact plaque on the teeth was to a great extentprevented.

Although the present invention has been disclosed in connection with afew preferred embodiments thereof, variations and modifications may beresorted to by those skilled in the art without departing from theprinciples of the new invention. All of these variations andmodifications are considered to be within the true spirit and scope ofthe present invention as disclosed in the foregoing description anddefined by the appended claims.

I claim:
 1. A method for inhibiting the abnormal deposition ordissolution of difficultly soluble calcium salts in the mouths ofwarm-blooded animals, which consists essentially in applying to theteeth of said animals a pharmacologically-acceptableamino-alkanediphosphonic acid derivative selected from the groupconsisting of (A) at least one aminoalkane-diphosphonic acid of theformula ##STR9## wherein R₁ and R₂ are each selected from the groupconsisting of hydrogen and alkyl having 1 to 3 carbon atoms, and (B) apharmacologically-acceptable water-soluble salt of (A), said derivativebeing administered in the form of a dentifrice, an adherent paste, anaqueous solution, a losenge or a chewing gum containing an effective buttoxicologically harmless amount therefor, in the range of about 0.01% toabout 5% by weight, of said derivative.
 2. A method according to claim 1wherein said derivative is applied to the teeth of said animals as anaqueous composition having a pH in the range of 5 to
 9. 3. A method forinhibiting the formation of tartar on the teeth of a warm-bloodedanimal, which comprises contacting said teeth with an aqueous solutionhaving a pH of 5 to 9 and containing 0.5% to 5% by weight of anaminoalkane diphosphonic acid derivative according to claim
 1. 4. Amethod for inhibiting the formation of tartar on the teeth of awarm-blooded animal, which comprises contacting said teeth with adentifrice in aqueous medium having a pH in the range of 5 to 9 andcontaining 0.5% to 5% by weight of an aminoalkane diphosphonic acidderivatives according to claim 1.